Identification and characterization of an idiopathic pulmonary fibrosis-like condition in cats

Interstitial lung diseases are a heterogeneous group of disorders with a variety of causes. In veterinary medicine, such lung diseases with a prominent fibrotic component of unknown etiology are often called idiopathic pulmonary fibrosis (IPF). In human medicine, this term is reserved for a distinct disease entity with specific histologic findings labeled as usual interstitial pneumonia (UIP). We identified 23 cats displaying histologic criteria of UIP The purpose of this retrospective study is to describe the presentation and response to therapy of these cats to better define this disease entity. All but 2 cats were middle aged to older (median 8.7 years), with no apparent sex or breed predisposition. Complaints included respiratory distress (n = 18) and cough (13). Duration of signs was less than 6 months in 17 cats. Physical-examination abnormalities included tachypnea, inspiratory or mixed inspiratory and expiratory effort, and adventitial lung sounds. No consistent hematologic or biochemical abnormalities, parasites, or positive serologic results for feline retroviruses, heartworms, or toxoplasmosis were present. Radiographic changes included dense patchy or diffuse interstitial, bronchiolar, and alveolar infiltrates. Analysis of bronchial lavage fluid revealed mild neutrophilic inflammation (n = 6) with no consistent pathogen growth. Clinical condition of 5 cats worsened after lavage. Coincident pulmonary neoplasia was identified in 6 cats. Response to therapy (corticosteroids, antibiotics, bronchodilators, and diuretics) was poor, and most cats died within days to months. Cats with histologic changes compatible with UIP had signs that mimicked many of the clinical findings of human IPF, and treatment response was similarly unrewarding.

Demographic, clinical, and radiographic features of bronchiectasis in dogs: 316 cases (1988-2000)

OBJECTIVE

To determine demographic, clinical, and radiographic features of bronchiectasis in dogs.

DESIGN

Retrospective study.

ANIMALS

289 dogs identified through the Veterinary Medical Database (VMDB) and 27 dogs examined at the North Carolina State University Veterinary Teaching Hospital.

PROCEDURE

Demographic characteristics of dogs identified through the VMDB were compared with characteristics of the entire population of dogs entered in the VMDB. Medical records of dogs examined at the teaching hospital were reviewed; the diagnosis was confirmed through review of thoracic radiographs.

RESULTS

Analysis of data from the VMDB indicated that American Cocker Spaniels, West Highland White Terriers, Miniature Poodles, Siberian Huskies, English Springer Spaniels, and dogs > 10 years old had an increased risk of bronchiectasis. Among dogs examined at the teaching hospital, coughing was the most common clinical sign. There was evidence for excessive airway mucus but not hemorrhage. A variety of bacterial organisms were isolated from tracheal wash and bronchoalveolar lavage samples. On thoracic radiographs, cylindrical bronchiectasis, generalized disease, and right cranial lung lobe involvement were most common. Seven of 14 dogs for which follow-up radiographs were available did not have any progression of radiographic lesions. Median duration of clinical signs prior to diagnosis of bronchiectasis was 9 months (range, 1 day to 10 years). Median survival time was 16 months (range, 2 days to 72 months).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that despite substantial clinical abnormalities, dogs with bronchiectasis may survive for years. Certain purebred dogs and older dogs may have an increased risk of developing bronchiectasis.

The Clinician Investigator program in companion animal internal medicine at north Carolina State University

A retrospective study was conducted to describe the development and evolution of the combined internal medicine/PhD program, the Clinician Investigator (CI) Program, at North Carolina State University. Separate survey instruments were developed for individuals who had committed to completing both the residency and PhD components and for graduate advisors of individuals who were granted the PhD degree. Results are summarized here. Most CIs reported believing that each component of the program (clinical training and research training) provided mutual benefits and that their teaching skills were enhanced, particularly as a result of instructing students in the Veterinary Teaching Hospital. Opinions among both the CIs and the graduate advisors were divided about the benefits of a combined program compared with a sequential program; however, all but one of 11 CIs who completed the survey would enroll in the combined program again. The graduate advisors were overwhelming positive about the CIs they had advised and indicated that they would welcome a CI as a PhD student in their laboratory again. Suggested areas for improvement included guaranteed salary/stipend support for the average time to completion (six years) instead of for five years, as well as more emphasis on and guidance in identifying a graduate advisor earlier in the CI program so as to smooth the transition between the clinical and research training components of the program. It is hoped that other training programs will benefit from the summary of our experience with this program.

Molecular identification of Ehrlichia ewingii infection in dogs: 15 cases (1997-2001)

OBJECTIVE

To determine historical, physical examination, hematologic, and serologic findings in dogs with Ehrlichia ewingii infection.

DESIGN

Retrospective study.

ANIMALS

15 dogs.

PROCEDURE

In all dogs, infection with E ewingii was confirmed with a polymerase chain reaction (PCR) assay. Follow-up information and clarification of information recorded in the medical records was obtained by telephone interviews and facsimile correspondence with referring veterinarians and owners.

RESULTS

Fever and lameness were the most common findings with each occurring in 8 dogs. Five dogs had neurologic abnormalities including ataxia, paresis, proprioceptive deficits, anisocoria, intention tremor, and head tilt. Neutrophilic polyarthritis was identified in 4 dogs. No clinical signs were reported in 3 dogs. The predominant hematologic abnormality was thrombocytopenia, which was identified in all 12 dogs for which a platelet count was available. Reactive lymphocytes were seen in 5 of 13 dogs. Concurrent infection with another rickettsial organism was identified in 4 dogs. Of the 13 dogs tested, 7 were seroreactive to E canis antigens. Morulae consistent with E ewingii infection were identified in neutrophils in 8 dogs. Treatment with doxycycline, with or without prednisone, resulted in a rapid, favorable clinical response in the 9 dogs for which follow-up information was available.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that PCR testing for E ewingii infection should be considered in dogs with fever, neutrophilic polyarthritis, unexplained ataxia or paresis, thrombocytopenia, or unexplained reactive lymphocytes, and in dogs with clinical signs suggestive of ehrlichiosis that are seronegative for E canis. Following treatment with doxycycline, the prognosis for recovery is good.

Endoscopic evaluation of the esophagus and stomach in three loggerhead sea turtles (Caretta caretta) and a Malaysian giant turtle (Orlitia borneensis)

Three loggerhead sea turtles (Caretta caretta) and a Malaysian giant turtle (Orlitia borneensis) were presented with suspected or confirmed esophageal foreign bodies. Esophagoscopy was performed on all turtles, and gastroscopy was performed on three turtles. In all cases, endoscopy was easy to perform, and allowed visualization of most upper gastrointestinal features. The papillated esophagus was easy to navigate, but mucosal papillae in the loggerhead sea turtles prevented examination of the underlying mucosa. The stomach was easily entered and examined in both species, but the working endoscope length (100 cm) prevented inspection of the pyloric antrum and the duodenum in all turtles. The turtles in this report may serve as references for future endoscopic examinations of these species.

Use of animation-enhanced video clips for teaching abnormal breathing patterns

The ability to characterize disease of the respiratory tract accurately based on breathing pattern is helpful for the development of differential diagnoses and an efficient diagnostic plan and critical for the stabilization of patients in respiratory distress. Veterinary students do not have sufficient clinical experience to observe personally all types of respiratory diseases and their resultant abnormal breathing patterns. We developed a teaching tool, the animated breathing pattern videotape (ABV), to fill this gap. The ABV is a collection of video clips of small animal patients with normal and abnormal breathing patterns on a conventional videotape of approximately 20 minutes duration. Each video clip is shown for 20 to 40 seconds, followed by the same clip with superimposed animation of rib and diaphragm motion, followed by the initial clip again, without overlying animation. The ABV has since been used in teaching third-year veterinary students, interns, residents, practicing veterinarians, and veterinary technicians. Student evaluations and responses to questionnaires by interns, residents, practicing veterinarians, veterinary technicians, and peer reviewers have been uniformly positive.

Molecular Evidence SupportingEhrlichia canis-Like Infection in Cats

Currently, the pathogenic role of Ehrlichia canis in cats has been proposed predominantly on the basis of the serologic evidence of natural infection and the infrequent detection of morulae‐like structures within the cytoplasm of leukocytes in cats. The purpose of this report was to provide molecular evidence supporting E cams‐like infection in 3 cats that had clinical manifestations consistent with canine ehrlichiosis but lacked antibodies to E canis antigens. Serum from all 3 cats contained antinuclear antibodies (ANAs). The predominant disease manifestation was polyarthritis in 1 cat and bone marrow hypoplasia or dysplasia, accompanied by pancytopenia or anemia and thrombocytopenia, in 1 cat each. The alignment of E canis partial 16S ribosomal DNA (rDNA; 382 nucleotide positions), amplified from EDTA blood samples from each cat, was identical to each other and was identical to a canine isolate of E canis (GenBank accession number AF373613). In 1 cat, concurrent treatment with corticosteroids may have interfered with the therapeutic effectiveness of doxycycline for the elimination of E canis‐like infection. To further define the spectrum of ehrlichiosis in cats, polymerase chain reaction (PCR) testing may be necessary until serologic testing is thoroughly validated in experimentally or naturally infected cats. In addition, until E canis has been isolated from cats and several tissue culture isolates are available from disparate geographic regions for detailed comparative genetic study, the molecular evidence presented in this study supporting E canis‐like infection in cats must be interpreted with caution.

Molecular evidence supporting Ehrlichia canis-like infection in cats

Currently, the pathogenic role of Ehrlichia canis in cats has been proposed predominantly on the basis of the serologic evidence of natural infection and the infrequent detection of morulae-like structures within the cytoplasm of leukocytes in cats. The purpose of this report was to provide molecular evidence supporting E. canis-like infection in 3 cats that had clinical manifestations consistent with canine ehrlichiosis but lacked antibodies to E. canis antigens. Serum from all 3 cats contained antinuclear antibodies (ANAs). The predominant disease manifestation was polyarthritis in 1 cat and bone marrow hypoplasia or dysplasia. accompanied by pancytopenia or anemia and thrombocytopenia, in 1 cat each. The alignment of E. canis partial 16S ribosomal DNA (rDNA: 382 nucleotide positions), amplified from EDTA blood samples from each cat, was identical to each other and was identical to a canine isolate of E. canis (GenBank accession number AF373613). In 1 cat, concurrent treatment with corticosteroids may have interfered with the therapeutic effectiveness of doxycycline for the elimination of E. canis-like infection. To further define the spectrum of ehrlichiosis in cats, polymerase chain reaction (PCR) testing may be necessary until serologic testing is thoroughly validated in experimentally or naturally infected cats. In addition, until E. canis has been isolated from cats and several tissue culture isolates are available from disparate geographic regions for detailed comparative genetic study, the molecular evidence presented in this study supporting E. canis-like infection in cats must be interpreted with caution.

Frequency of pulmonary mineralization and hypoxemia in 21 dogs with pituitary-dependent hyperadrenocorticism

The purpose of this study was to determine the frequency of hypoxemia and pulmonary mineralization using 99mTc-methylene diphosphonate (99mTc-MDP) in dogs with pituitary-dependent hyperadrenocorticism (PDH). Twenty-one dogs with PDH were prospectively evaluated using thoracic radiography, arterial blood gas analysis, and bone phase and pulmonary perfusion scintigraphy (using 99mTc-macro-aggregated albumin [99mTc-MAA]). The radiographs and bone and perfusion studies were evaluated subjectively. An averaged quantitative count density ratio was calculated between the thorax and cranial thoraco-lumbar vertebrae from lateral thoracic 99mTc-MDP images. Thoracic:vertebral ratios were calculated using 99mTc-MDP studies from 21 control dogs. The thoracic:vertebral ratios were compared between the 2 groups (PDH and control). The mean age (+/-SD) of the 21 PDH dogs was 10.2 (+/-3) years, whereas the mean age of the control group was 9.8 (+/-3) years. Seven of the 21 dogs with PDH were hypoxemic (defined as an arterial partial pressure of oxygen [PaO2] < 80 mm Hg) with an average PaO2 (+/-SD) of 62 (+/-15) mm Hg. Of the 7 hypoxemic dogs, 2 were found to have pulmonary mineralization based on bone scintigraphic images. Pulmonary perfusion abnormalities were not identified using 99mTc-MAA in any of the 21 PDH dogs. Six PDH dogs had an abnormal interstitial pulmonary pattern and 5 of these dogs were hypoxemic. The average quantitative thoracic:vertebral ratio was not significantly different between the PDH and control dogs (0.5 +/- 0.4 versus 0.4 +/- 0.1, P = .16). Causes of hypoxemia other than pulmonary thromboembolism should be considered in dogs with PDH. Pulmonary mineralization may contribute to hypoxemia in dogs with PDH.

Use of a modified stomach tube for bronchoalveolar lavage in dogs

A technique that did not require use of a bronchoscope for bronchoalveolar lavage (BAL) in dogs was developed. An inexpensive, readily available 16-F Levin-type stomach tube was modified for the procedure. The technique was effective for collecting BAL fluid in 9 dogs that ranged from 9.3 to 26.2 kg (20.5 to 57.6 lb). Recovered fluid was consistent with fluid collected bronchoscopically. Mean recovery volume was 84/125 ml (67%), mean WBC counts were high (> 300 cells/microl), and > 70% of cells were macrophages. Complications from use of the technique were not detected on the basis of pulse oximetry, thoracic radiography, and clinical observation. This effective, simple, and safe technique for BAL can be readily performed in clinical settings that do not have bronchoscopic capabilities. It also provides a less costly alternative than bronchoscopic BAL.

Tracheal rupture in cats: 16 cases (1983-1998)

OBJECTIVE

To determine causes of tracheal rupture in cats and the mechanism of injury.

DESIGN

A retrospective study was conducted to identify cats with tracheal rupture. A second study was conducted to establish mechanism of injury, and a third study was conducted to determine volume of air needed to obtain an airtight seal when inflating the cuff of an endotracheal tube in a cat.

ANIMALS

16 cats with clinical signs of tracheal rupture, 10 cat cadavers, and 20 clinically normal cats that were undergoing anesthesia.

PROCEDURES

Details were extracted from medical records of 16 cats with tracheal rupture (9 treated surgically and 7 treated conservatively). For the cadaver study, the trachea of each cat cadaver was intubated and observed during overinflation of the endotracheal tube cuff. For clinically normal cats, volume of air needed to obtain an airtight seal for the endotracheal tube was recorded.

RESULTS

Most ruptures were associated with cats anesthetized for dental procedures. Clinical signs associated with tracheal rupture included subcutaneous emphysema, coughing, gagging, dyspnea, anorexia, and fever. Tracheoscopy was the method of choice for documenting tracheal rupture. Surgical and conservative management were successfully used, unless the injury extended to the carina. In the cadaver study, overinflation of the endotracheal tube cuff with > 6 ml of air resulted in tracheal rupture in 7 of 10 cadavers. For clinically normal cats, the volume of air (mean +/- SD) needed to obtain an airtight seal was 1.6 +/- 0.7 ml.

CLINICAL IMPLICATIONS

Overinflation of an endotracheal tube cuff may result in tracheal rupture in cats.

Concentration of enrofloxacin and its active metabolite in alveolar macrophages and pulmonary epithelial lining fluid of dogs

The purpose of this study was to determine the concentration of enrofloxacin and its active metabolite, ciprofloxacin, in alveolar macrophages (AM) and epithelial lining fluid (ELF) of the lungs in comparison to plasma concentrations in healthy dogs. Eleven dogs were given a single oral dose (5 mg/kg) of enrofloxacin. Four hours later, plasma and bronchoalveolar lavage (BAL) fluid were collected. Cells were separated from the BAL fluid and lysed for determination of drug concentrations within AM. Supernatant was used to determine concentrations of drugs in ELF. Drug assays were performed by high-performance liquid chromatography. The concentration of enrofloxacin (mean +/- SD) was 0.33 +/- 0.14 microgram/mL in plasma, 3.34 +/- 2.4 micrograms/mL in AM and 4.79 +/- 5.0 micrograms/mL in ELF. The concentration of ciprofloxacin was 0.42 +/- 0.26 microgram/mL in plasma, 1.15 +/- 1.03 micrograms/mL in AM and 0.26 +/- 0.26 microgram/mL in ELF. Mean concentrations of both drugs in AM were greater than in plasma (AM to plasma ratio, 10.3 for enrofloxacin and 4.7 for ciprofloxacin). Mean concentrations of enrofloxacin, but not ciprofloxacin, in ELF were greater than in plasma (ELF to plasma ratio, 13.5 for enrofloxacin and 0.52 for ciprofloxacin). Enrofloxacin concentrations in AM and ELF largely exceeded the MICs of the major bacterial pathogens and surpassed by about two times the breakpoint MIC of that drug, and ciprofloxacin concentrations in AM surpassed the MIC of many susceptible organisms. These results suggest that sufficient antimicrobial activity is present in AM and ELF of dogs following oral administration of enrofloxacin to be effective in the treatment of lower respiratory tract infections involving susceptible organisms.

Effects of valacyclovir in cats infected with feline herpesvirus 1

OBJECTIVE

To determine whether orally administered valacyclovir can be used safely and effectively to treat cats with primary, feline herpesvirus 1 (FHV-1) infection.

ANIMALS

14 specific-pathogen-free adult cats.

PROCEDURE

Cats were infected with FHV-1 strain 87-727 (300 microliters, 10(7) plaque-forming units/ml) by ocular and nasal inoculations, and were treated every 6 hours with dextrose (controls) or valacyclovir (60 mg/kg of body weight, PO). Virus shedding from both eyes and the oropharynx was monitored every 2 days by virus isolation, and subjective clinical scores were assigned daily for ocular and nasal discharge and conjunctival hyperemia. Urinalysis, CBC, and serum biochemical analysis were done prior to inoculation, and on days 2, 5, 7, 9, and 12 of infection. Differences in CBC and serum biochemical indices between groups were compared, as were differences between preinfection values and maximal postinfection values, rectal temperature, and scores for disease severity.

RESULTS

All cats developed acute conjunctivitis and rhinitis typical of FHV-1 infection. Beginning between days 6 and 9, valacyclovir-treated cats became noticeably more lethargic and dehydrated than did cats of the control group. Total WBC and neutrophil counts were significantly lower in cats of the valacyclovir group. The experiment was terminated on day 12 for humane reasons. Histologic changes attributable to FHV-1 infection were similar in all cats. Additional histologic abnormalities seen only in the valacyclovir-treated cats were coagulative necrosis of the renal tubular epithelium, centrilobular atrophy and hepatic necrosis, and severe bone marrow depression.

CONCLUSIONS

Cats appear to be uniquely sensitive to the toxic effects of valacyclovir, and even high doses appear not to suppress FHV-1 replication in acutely infected cats.

CLINICAL RELEVANCE

Use of valacyclovir is of questionable value in cats with acute FHV-1 infection and, at high doses, the drug may be toxic.

Bronchoalveolar lavage in a dolphin

Bronchoalveolar lavage (BAL) was performed twice to evaluate a stranded Atlantic bottle-nosed dolphin for pulmonary disease. A pediatric gastroscope with a working length of 1,090 mm and an outer diameter of 9.8 mm was of appropriate size for BAL in this dolphin. Fifty milliliters of sterile saline (0.9% NaCl) solution was used in each of 2 sites for the first lavage. Fluid recovery was 58 and 66% from the 2 sites; however, results of cytologic analyses were typical of a bronchial wash rather than BAL. Larger volumes of saline solution (85 to 100 ml/site) were used in the second lavage. Although fluid recovery was only 25 and 30% from the 2 sites, results of cytologic analyses were consistent with BAL. Mononuclear cells accounted for 72 and 90% of total WBC. Although the dolphin of this report did not appear to have pulmonary disease, experience obtained by performing BAL provided valuable information for the practical application of this technique in dolphins.

Fluconazole in cats: pharmacokinetics following intravenous and oral administration and penetration into cerebrospinal fluid, aqueous humour and pulmonary epithelial lining fluid

The pharmacokinetics of fluconazole following intravenous (i.v.) and oral (p.o.) administration and the penetration of fluconazole into cerebrospinal fluid, aqueous humour and epithelial lining fluid (ELF) of the lungs were evaluated in adult male cats. Pharmacokinetic parameters were calculated from serum concentration-time data obtained following i.v. and p.o. administration of 50 mg per cat using a cross-over study design. Fluconazole concentrations were measured using a high-performance liquid chromatography assay. Mean total body clearance of fluconazole was 37.7 mL/h.kg, mean volume of distribution at steady state was 1.14 L/kg, mean residence time was 31.0 h and mean half-life of elimination was 25 h as derived by non-compartmental analysis of data. Absorption was complete. Mean ratios of fluid:serum fluconazole concentrations following administration of 50 mg fluconazole per day for 8 days were as follows: cerebrospinal fluid, 0.88; aqueous humour 0.79; ELF, 1.20. Fluconazole concentrations in cerebrospinal fluid, aqueous humour and ELF exceeded reported minimum inhibitory concentrations of fluconazole for pathogenic fungi. Results of this study suggest fluconazole can effectively be administered to cats at 50 mg per cat per day.

Cytologic identification of Toxoplasma gondii in bronchoalveolar lavage fluid of experimentally infected cats

OBJECTIVE

To determine whether it was possible to retrieve organisms, by means of bronchoalveolar lavage (BAL), from cats inoculated with Toxoplasma gondii.

DESIGN

Experimental study.

ANIMALS

27 cats. Sixteen of the 27 were experimentally infected with feline immunodeficiency virus.

PROCEDURE

All cats were inoculated with T gondii tachyzoites. Cats were grouped on the basis of feline immunodeficiency virus status and route (IV or intra-arterial) and number of tachyzoites administered. Bronchoalveolar lavage was performed by means of a standard technique. Lavage fluid was evaluated cytologically for tachyzoites.

RESULTS

Clinical signs of toxoplasmosis varied widely among individual cats, but were generally most pronounced in group-1 and -2 cats (n = 5 each) and less pronounced in group-3 (n = 5) cats. Group-4 and -5 cats (n = 6 each) did not have clinical signs of toxoplasmosis. In 14 of the 15 cats in groups 1, 2, and 3, tachyzoites were detected in BAL fluid collected 7 days after inoculation. Tachyzoites were detected 14 days after inoculation in the single cat without tachyzoites 7 days after inoculation. A necropsy was performed on 9 of these cats, and tachyzoites were identified histologically in 4 of the 9. Tachyzoites were not detected in BAL fluid collected 3 days (n = 6) or 7 days (n = 6) after inoculation from the 12 cats in groups 4 and 5. Tachyzoites were not identified histologically in any of these 12 cats.

CLINICAL IMPLICATIONS

BAL may be useful in the diagnosis of toxoplasmosis, particularly in cats with signs of pulmonary involvement.

Effect of FIV infection on lung inflammatory cell populations recovered by bronchoalveolar lavage

Human immunodeficiency virus (HIV) and ovine progressive pneumonia virus have been associated with lymphocytic pneumonitis. Pulmonary cell populations in cats infected with feline immunodeficiency virus (FIV) were evaluated by bronchoalveolar lavage (BAL) to identify changes associated with lentivirus infection in this species. Bronchoalveolar lavage was performed through an endotracheal tube using 15 ml kg-1 body weight of sterile 0.9% sodium chloride solution. Results of BAL fluid cytologic analysis from 19 cats experimentally infected with FIV for at least 8 months were compared with results from 34 uninfected cats. Infected cats had significantly higher total cell counts and relative neutrophil counts (P < 0.01). Lymphocytosis did not occur. Bronchoalveolar lavage fluid was collected from nine additional cats prior to, and 2, 6, and 17-18 weeks following infection with FIV. Neither neutrophilia nor lymphocytosis was associated with FIV infection in these cats.

Cytological analysis of bronchoalveolar lavage fluid in the diagnosis of spontaneous respiratory tract disease in dogs: a retrospective study

Results of cytological analysis of bronchoalveolar lavage (BAL) fluid were compared with clinical diagnoses in dogs that presented with signs of respiratory disease to referral hospitals. Of 68 dogs in which a clinical diagnosis was possible, BAL cytological findings were considered definitive for the diagnosis in 17 cases (25%), supportive of the diagnosis in 34 cases (50%), and not helpful in 17 cases (25%). Findings were most often considered supportive of or definitive for the clinical diagnosis in dogs with alveolar or bronchial radiographic patterns, or the presence of pulmonary masses. BAL results among lung lobes differed in 23 of 63 dogs (37%) with diffuse radiographic patterns. Tracheal wash cytology differed from BAL fluid cytology in 45 of 66 dogs (68%). Bronchoalveolar lavage was a clinically useful procedure for the diagnostic evaluation of dogs with signs of respiratory disease.

Tumor necrosis factor-alpha responses are depressed and interleukin-6 responses unaltered in feline immunodeficiency virus infected cats

Feline immunodeficiency virus (FIV), a lentivirus similar to HIV, causes an acquired immunodeficiency syndrome in cats. Similar to human immunodeficiency virus (HIV), the pathogenesis of FIV is associated with dysregulation of the cytokine network. While alterations in tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) expression have been reported in HIV-infected patients, changes attributable to HIV and those caused by cofactors such as secondary infections cannot always be readily distinguished. This study evaluated the effect of FIV infection on TNF-alpha and IL-6 production in cats not exposed to other potential cofactors such as secondary infections. TNF-alpha and IL-6 activities were evaluated in bronchoalveolar lavage (BAL) cells from FIV-infected and uninfected specific pathogen free (SPF) cats. Supernatants from lipopolysaccharide (LPS)-stimulated BAL cells from uninfected SPF cats had high levels of TNF-alpha and IL-6 activity, while stimulated BAL cell supernatants from FIV-infected SPF cats had significantly lower levels of TNF-alpha but unaltered IL-6 activity. Similarly, Con A/phorbol myristate acetate (PMA) stimulated non-adherent (NA-) peripheral blood mononuclear cells (PBMC) from FIV infected cats synthesized less TNF-alpha than similarly treated NA-PBMC from uninfected cats. Feline immunodeficiency virus could be recovered from the culture supernatants of BAL cells from infected cats by co-cultivation with susceptible lymphocytes. In situ hybridization identified FIV mRNA in a small fraction of alveolar macrophages in the BAL cell cultures.(ABSTRACT TRUNCATED AT 250 WORDS)